It is well known in the electronics art to place a heat sink in contact with an electronic device so that waste heat generated by operation of the electronic device is thermally transferred to the heat sink thereby cooling the electronic device. With the advent of high clock speed electronic devices such as microprocessors (CPU's), digital signal processors (DSP's), and application specific integrated circuits (ASIC), the amount of waste heat generated by those electronic devices and the operating temperature of those electronic devices are directly proportional to clock speed. Efficient operation of a CPU as well as other high power dissipation electronic devices requires that waste heat be continuously and effectively removed. However, as areal densities and clock speed of electronic devices continue to increase, a heat flux of the device also increases. Although air cooled heat sinks are a commonplace means for dissipating the waste heat from the aforementioned electronic devices, the increased heat flux in high performance electronic devices is often concentrated in a small area. The ability to effectively dissipate ever increasing levels of heat flux in high performance electronic devices has challenged current heat sink designs where the entire heat sink is fabricated using processes such as machining, forging, casting, and extrusion. Those processes make it difficult to increase the number of fins or an area of the fins in order to effectively dissipate heat cause by the aforementioned heat flux.
Heat flux is a thermal output per unit of area. For example, if a total thermal output is 100 Watts over a heat source having dimensions of 3.5 cm*3.5 cm, then the heat flux is 100 W/(3.5 cm*3.5 cm)=8.163 W/cm2. At present, based on area and cost constraints, clock speeds in CPU's are being increase while the package area remains the same or is reduced. The higher clock speeds result in increased thermal output and a resulting increase in heat flux.
Consequently, there is a need for a cooling device with improved thermal conductivity that reduces heat flux concentration and efficiently dissipates waste heat from a device in thermal communication with the cooling device. There is also a need for a cooling device in which the number of fins and/or an area of the fins can be increased to dissipate heat from a device in thermal communication with the cooling device.